Construction and Visible Photocatalytic Hydrogen Performance of Hydrangea-like ZnIn2S4/CoWO4S-scheme Heterojunction

Rational design of heterojunction structures to accelerate photocatalytic hydrogen evolution plays an indispensable role in the development of photocatalytic materials. ZnIn2S4 ZIS has been widely used in the field of photo catalytic hydrogen evolution due to its excellent photoelectric properties and negative conduction band position, but it still has serious problems of photogenerated carrier recombination and aggregation. Therefore, the band structure and electron transfer path of ZnIn2S4/CoWO4 ZIS/CWO S-scheme heterojunction were predicted by theoretical calculation, and the electron exchange at the interface of the heterojunction was determined by electron localization function and charge density difference. Subsequently, CWO nanoparticles were dispersed and fixed on the surface of ZIS flower balls by ultrasonic-agitation-calcination method, and the hydrangea-like ZIS/CWO S-scheme heterojunction was obtained. Owing to the tight interface and the formation of internal electric field between ZIS and CWO, the photogenerated electron-hole pairs in ZIS/CWO S-scheme heterojunction can be effectively separated thus enhancing the photocatalytic hydrogen evolution performance. Meanwhile, the experimental results confirmed the formation of S-scheme heterojunction and carrier transport path, revealing the in-depth mechanism of photocatalytic hydrogen evolution. This work offers novel insights and approaches for the design, construction, and theoretical calculation of S-scheme heterojunction photocatalysts.